1. Field of the Invention
The invention relates to a test system for testing integrated chips in a burn-in test operation and also to an adapter element for such a test system.
2. Description of the Related Art
In a test system for a burn-in test operation, the integrated chips to be tested are usually arranged on a burn-in board, i.e., on a burn-in board having receptacles for the integrated chips, and are inserted into a tester device of the test system. The tester device has test modules with driving and evaluation electronics, i.e., with test circuits. When the burn-in board is inserted, a test module of the tester device is connected to the integrated chips on the burn-in board. During the burn-in test operation, the function of the integrated chip is tested under extreme operating conditions, such as elevated ambient temperature, high operating voltage or the like, in order to pre-age the chip and thus to reduce the early failure rate.
Due to the increasing packing density of the burn-in receptacles on the burn-in board, the maximum current limiting of the test module and/or the number of available test channels are often reached or exceeded. This problem arises, inter alia, also during a wafer level burn-in test operation during which the integrated circuits on a wafer are intended to be tested, and thereby pre-aged, simultaneously in one burn-in test operation prior to being separated into individual chips. Successively effected burn-in test operations with the integrated circuits situated on a common wafer cannot be carried out, since the burn-in time would be considerably lengthened and the integrated circuits would experience different pre-ageing conditions.
In order not to exceed the maximum current limiting of the test module or the number of available tester channels, either the packing density of the receptacles on the burn-in boards is reduced or the burn-in boards are only partially populated with integrated chips to be tested. As an alternative, either additional current sources or new test modules have been provided, in order to meet the altered conditions. This has the disadvantage that the burn-in boards are utilized non-optimally, or it has been necessary to accept high costs on account of new test modules and/or additional supply sources.